System, method and apparatus for sensor insertion

ABSTRACT

Embodiments provide a sensor insertion tool (SIT) that provides a motive force for insertion of an analyte sensor into/through skin. A SIT may be releasably locked to one or more components of a sensor insertion system, such that components of the sensor insertion system remain securely coupled during sensor insertion. A SIT may include a release member that unlocks or uncouples the SIT and the other components after sensor insertion. In various embodiments, a SIT may be a component of a sensor insertion system configured for assembly by an end user, a health care professional, and/or a caretaker prior to sensor insertion, and may act in cooperation with other sensor insertion system components. Additional components and methods of assembly and use are also provided herein.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional of U.S. application Ser. No.12/495,238, filed Jun. 30, 2009, which is related to U.S. patentapplication Ser. No. 61/037,246, filed Mar. 17, 2008, entitled “AnalyteSensor Subassembly and Methods and Apparatuses for Inserting an AnalyteSensor Associated with Same,” the entire disclosure of which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

Embodiments herein relate to devices for inserting analyte sensors intoa subject, and, more specifically, to a sensor insertion tool forinsertion of an analyte sensor through the skin of a subject.

BACKGROUND

Implantable analyte sensors offer a convenient and accurate alternativeto analyte testing methods such as fingerstick blood glucose meters.Indwelling sensors also offer an additional advantage in that analyteconcentrations in an individual may be tracked over a period of timewithout requiring the individual to draw a blood sample for eachmeasurement. Where close attention to blood analyte concentrations iscorrelated with better outcomes, an indwelling analyte sensor may besuperior to other monitoring options. In diabetes, for example, bloodglucose levels that are either higher or lower than a target level mayresult in serious medical complications. Continuously monitoring bloodglucose levels using an implanted sensor and an external electronicmeasuring device may improve the user's ability to control blood glucoselevels, thus reducing the incidence and severity of such complications.

Flexible indwelling sensors may be more comfortable for the user thanrigid or semi-rigid sensors, and less likely to experience failure dueto mechanical stress induced by the user's movements. Flexibleindwelling sensors have been described, for example, in U.S. Pat. No.5,165,407 to Ward et al. However, the insertion of flexible sensorsrequires an initial piercing of the skin due to the tendency of flexiblesensors to bend. Therefore, insertion of flexible sensors is oftenaccomplished by inserting the sensor through a rigid hollow mechanismsuch as a needle, a cannula or a trocar used to create a channel throughwhich the sensor could pass. See, for example, U.S. Pat. No. 6,695,860to Ward et al.

The use of such piercing mechanisms for sensor insertion may causephysical and emotional discomfort among users, discouraging the use ofindwelling sensors for continuous blood analyte monitoring. Piercingmechanisms that accommodate a sensor may be large and painful to insertthrough skin. In addition to the physical discomfort associated withpiercing mechanisms, an individual in need of consistent blood analytemonitoring may be reluctant to use such a mechanism without assistance.

Analyte sensor flexibility reduces user discomfort in long-term sensoruse. But as flexibility increases, the capacity of the sensor todirectly penetrate unbroken skin diminishes. While flexible indwellinganalyte sensors may improve a user's ability to monitor blood analytelevels for optimal medical outcomes, the available insertion methods maybe unacceptable to some who are in need of monitoring.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detaileddescription in conjunction with the accompanying drawings. Embodimentsare illustrated by way of example and not by way of limitation in thefigures of the accompanying drawings.

FIG. 1a-1e show a sensor insertion system and components of a sensorinsertion system in accordance with various embodiments;

FIGS. 2a and 2b show flow charts for methods of sensor insertion using asensor insertion system in accordance with various embodiments;

FIG. 3 shows a partially exploded perspective view of a sensor insertionsystem for insertion of a sensor into intact skin in accordance withvarious embodiments;

FIG. 4 shows a perspective view of a sensor insertion system inaccordance with various embodiments;

FIG. 5a illustrates a perspective view of the interior of a sensorinsertion tool (SIT) configured to provide a motive force for sensorinsertion in accordance with various embodiments;

FIG. 5b illustrates a perspective view of the interior of a SIT coupledto a channel guide assembly in accordance with various embodiments;

FIG. 5c illustrates a cutaway view of a SIT mated to a channel guideassembly in accordance with various embodiments;

FIG. 5d illustrates a partially exploded perspective view of a SIT inaccordance with various embodiments;

FIGS. 6a-6d illustrate a channel guide assembly comprising a channelguide and a channel guide cover in accordance with various embodiments;

FIG. 7a illustrates a sensor subassembly in accordance with variousembodiments;

FIG. 7b illustrates a partially exploded view of a sensor subassembly inaccordance with various embodiments;

FIG. 7c illustrates a perspective view of a sensor coupled with sensorcontacts and sensor contact spring elements in accordance with variousembodiments;

FIG. 7d illustrates a sensor subassembly housing in position for sensorinsertion within a channel guide assembly in accordance with variousembodiments;

FIGS. 8a-8b illustrate a reusable sensor assembly (RSA) that may bemated to a disposable sensor assembly (DSA) in accordance with variousembodiments;

FIGS. 9a-9c illustrate a DSA which may be mated to a channel guideassembly and/or a RSA in accordance with various embodiments; and

FIGS. 9d-9f illustrate a DSA coupled to a channel guide assembly and/ora RSA in accordance with various embodiments.

Detailed Description of Disclosed Embodiments

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which are shownby way of illustration embodiments that may be practiced. It is to beunderstood that other embodiments may be utilized and structural orlogical changes may be made without departing from the scope. Therefore,the following detailed description is not to be taken in a limitingsense, and the scope of embodiments is defined by the appended claimsand their equivalents.

Various operations may be described as multiple discrete operations inturn, in a manner that may be helpful in understanding embodiments;however, the order of description should not be construed to imply thatthese operations are order dependent.

The description may use perspective-based descriptions such as up/down,back/front, and top/bottom. Such descriptions are merely used tofacilitate the discussion and are not intended to restrict theapplication of disclosed embodiments.

The terms “coupled” and “connected,” along with their derivatives, maybe used. It should be understood that these terms are not intended assynonyms for each other. Rather, in particular embodiments, “connected”may be used to indicate that two or more elements are in direct physicalor electrical contact with each other. “Coupled” may mean that two ormore elements are in direct physical or electrical contact. However,“coupled” may also mean that two or more elements are not in directcontact with each other, but yet still cooperate or interact with eachother.

For the purposes of the description, a phrase in the form “A/B” or inthe form “A and/or B” means (A), (B), or (A and B). For the purposes ofthe description, a phrase in the form “at least one of A, B, and C”means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).For the purposes of the description, a phrase in the form “(A)B” means(B) or (AB) that is, A is an optional element.

The description may use the terms “embodiment” or “embodiments,” whichmay each refer to one or more of the same or different embodiments.Furthermore, the terms “comprising,” “including,” “having,” and thelike, as used with respect to embodiments, are synonymous.

Embodiments herein provide methods, apparatuses, and systems forinserting a flexible sensor into intact skin. In various embodiments, asensor insertion tool (SIT) provides the motive force for driving asensor into intact skin without the use of a needle, trocar, cannula,lancet or similar device to first pierce the skin. In embodiments, a SITmay be reusable and/or disposable, and may be mechanically coupled toone or more other components of a sensor insertion system. In someembodiments, a SIT may be configured to lock securely to one or morecomponents in preparation for sensor insertion. In an embodiment, such aconfiguration may also include a release element for releasing the SITand/or a component of a sensor insertion system from another componentof the sensor insertion system.

FIG. 1a shows a diagram of a partial sensor insertion system 100 inaccordance with various embodiments. Sensor insertion system 100 mayinclude a SIT 120, a channel guide assembly 160, and a sensorsubassembly 180. Sensor subassembly 180 may be coupled to channel guideassembly 160. In FIG. 1 a, sensor subassembly 180 is retained within aninterior aperture of channel guide assembly 160 (shown by dashed lines),but alternatively a sensor subassembly may be positioned at an endand/or edge of a channel guide assembly and/or coupled to a surface bymeans of a fastener or retaining element. A sensor subassembly 180 maybe provided and may be retained prior to insertion within channel guideassembly 160. Channel guide assembly 160 may also be coupled, such asremovably coupled, to SIT 120.

In embodiments, a sensor insertion system may be configured to insert asensor, such as a flexible analyte sensor, into and/or at leastpartially through a layer of skin and/or into interstitial fluid. A SITmay provide motive force for insertion of a sensor into skin, and achannel guide assembly may provide a channel or track along which thesensor subassembly may travel prior to and/or during insertion of thesensor through the skin. A sensor subassembly may provide electricalcommunication between the sensor and electrical components in acorresponding part of a sensor assembly. A sensor assembly may compriseone or more components, such as a RSA and DSA.

Embodiments of a sensor insertion system may vary in the number,arrangement, function, and identity of components.

An exemplary embodiment of a sensor insertion system may comprise one ormore of a SIT, a channel guide assembly, a sensor subassembly, and asensor assembly. In operation, a sensor insertion system may beassembled by coupling, such as snapping, locking, etc., together two ormore components of a sensor assembly (such as a RSA and a DSA), couplingthe sensor assembly to the channel guide assembly, and coupling the SITto the channel guide assembly. In an embodiment, a channel guideassembly may be provided with a channel guide and a channel guide cover,and may also contain a sensor subassembly pre-positioned for insertion.

The SIT may then be cocked to load energy into a spring member byraising a cocking arm, which may pull a sensor hammer into apre-insertion position. A trigger element of the SIT may then beactuated, causing release of the sensor hammer and the loaded energy;this may cause the hammer to strike the sensor subassembly positionedwithin the channel guide, driving the sensor subassembly down a channelof the channel guide with sufficient force to drive the sensor through achannel in the sensor assembly and into/through intact skin without theuse of a trocar or other such element. The provided force may also besufficient to drive a housing of the sensor subassembly into a recess ofthe sensor assembly, causing sensor contact elements of the sensorsubassembly to contact corresponding contact elements within the sensorassembly. This contact may provide an electrical connection from thesensor to the circuitry of the sensor assembly. Finally, a releasemember of the SIT may be actuated to apply force against retentionelements of various components, uncoupling the SIT and/or channel guidefrom the sensor assembly and sensor subassembly. The sensor assembly andsensor subassembly may remain affixed to the skin, such as by anadhesive or adhesive patch, after the uncoupling of the SIT and/orchannel guide.

FIG. 1b shows a diagram of a SIT 120 in accordance with variousembodiments. SIT 120 may include a cocking member 133, an actuator 123,a release member 145, a motive force member 141, a housing 113 and/or alocking element 115. In FIG. 1 b, cocking member 133, actuator 123, andrelease member 145 are coupled to motive force member 141, and housing113 is coupled to locking element 115 and to each of the othercomponents. Alternatively, a housing may be mechanically coupled to acomponent of a sensor insertion system, such as a channel guideassembly, and may not be coupled to the other components of the SIT.

A cocking member may be configured to permit cocking a SIT only whensensor insertion components are in a correct position for sensorinsertion. Some embodiments may comprise a cocking member release thatreleases energy loaded without causing sensor insertion.

In a sensor insertion system, a SIT may be configured to apply motiveforce to a sensor and/or to a sensor subassembly coupled to and/or orretained within a channel guide or other component. The applied forcemay propel the sensor through an aperture or channel within a channelguide or other component such that the sensor is driven through theaperture/channel and into skin without the use of means for piercing theskin prior to insertion.

Motive force may be generated by one, two, three, four, or more springs.A cocking member may be used to load and store energy in one or moresprings. The release of such stored energy may drive a sensor and/orsensor assembly toward the skin for sensor insertion. A cocking membermay only require a single manipulation by a user to store sufficientenergy for sensor insertion, while in other embodiments, a cockingmember may be manipulated two or more times to store energy forinsertion. A cocking member may be configured to minimize the forcerequired to load sufficient energy in the spring for sensor insertion,allowing the user to apply minimal force to the cocking member. Acocking member may be configured to be moved up, down, to the side,pushed inward, and/or pulled outward to load energy into the spring.

In some embodiments, a spring member may be associated with a ratchet orsimilar element, and a user may load energy into the spring member forsensor insertion by repeatedly pushing, pulling, sliding, raising, orotherwise manipulating the ratchet. In an embodiment, a trigger elementmay adjust the position of the ratchet or other associated component torelease the loaded energy from the spring.

While springs are discussed above as providing motive force, anysuitable device may be utilized to provide the desired motive force. Forexample, motive force may be provided by a chemical reaction and/or bycompression/expansion of a gas or other substance, electromagnetically,mechanically, or by other means, individually or in combination. A SITmay include a chamber for gas compression, a piston fitted within thechamber, and a one-way flow valve that allows air to enter but not toescape. For example, a cocking member may be used to prime a mechanismproviding motive force from a chemical reaction and/orexpansion/compression of a gas. A user may manipulate a handle or leverelement attached to the piston, compressing air within the chamber. Inan embodiment, the release of compressed air may be applied against asensor subassembly with sufficient force to drive a sensor into and/orthrough skin. In other embodiments, a compressed gas such as carbondioxide may be supplied in a single-use canister and coupled to a SIT toprovide motive force for sensor insertion.

One or more components of a SIT may comprise a shape memory material,such as a shape memory alloy, a shape memory polymer and/or anotherthermally-responsive material. In some embodiments, a component of a SITthat provides motive force may respond to a change in temperature bychanging its conformation. For example, a spring force member may beconfigured to assume a first state in response to application of heat tothe spring force member, and to assume a second state in response tocooling of the spring force member. In embodiments, heating/cooling aSIT component may provide motive force for sensor insertion.Alternatively, heating/cooling a SIT component may cause a change inconfiguration of the component such that another component is moved,triggered, locked, released, or retained.

A shape memory alloy may contain copper, zinc, aluminum, nickel, and/ortitanium, or any combination of these. Shape memory polymers may containpolyurethanes and/or block copolymers, and a SIT component comprising ashape memory polymer may change its shape/conformation in response toone or more of heat, light, electricity, change in pH, and/or a magneticfield. In some embodiments, a plurality of components of a SIT maycomprise a shape memory material. A SIT may be configured to bereusable; in some embodiments, the application ofheat/light/electricity/magnetic field to the SIT and/or exposure of theSIT to a pH change may return a SIT to its original conformation after ause of the SIT.

In embodiments, a sensor assembly may be adapted to adhere to the skinand/or to apply force to skin near the insertion site to stretch or pullthe skin prior to sensor insertion. In an embodiment, a channel guideassembly may be provided with a suction means to pull skin toward thechannel guide assembly. Alternatively, a suction means may be providedby actuating a SIT or may be activated separately using a button, aplunger, a cocking mechanism, and/or another user control element.

FIG. 1c illustrates a diagram of a sensor assembly in accordance withvarious embodiments. FIG. 1c includes a first sensor assembly component180, a second sensor assembly component 190. First sensor assemblycomponent 180 may include a battery 185, electronic circuitry 182,and/or electrical contacts 186. Second sensor assembly component 190 mayfurther include a retention element 197 for coupling components 180, 190and/or a retention clip 196 for securing a sensor subassembly (notshown) in recess 198. The first and the second sensor assemblycomponents may be configured to be mechanically coupled together, andmay be further configured to be releasable from one another. While FIG.1c illustrates a sensor assembly with two main components, a sensorassembly may instead be provided with one, two, three or morecomponents.

In embodiments, a sensor assembly may provide electrical communicationwith a sensor that has been inserted into skin. A component of a sensorassembly (such as the first or the second component) may comprise one ormore housing elements, electronic circuitry (e.g. one or more printedcircuit boards), electrical contacts, power sources, gaskets and/orsealants, and/or one or more means for being mechanically coupled toanother component of a sensor insertion system. Such means may include aclip, a surface feature and/or protrusion of a housing element or otherelement of the component, a screw member, a pin member, a hinge member,a lip or thread, a slot, a pivot, etc.

A power source may include a single battery or two or more batteriesconnected in parallel and/or in series, and may comprise anelectrochemical battery, a disposable battery, and/or a rechargeablebattery. Power may be provided by the motion of the user. A component ofa sensor assembly and/or a sensor insertion system may be provided withmeans to convey battery life and/or power level via a visual, audio,and/or tactile signal.

Components of a sensor assembly may vary as desired for particularapplications. In embodiments, one, two or more of the components of asensor assembly may be disposable and/or reusable.

FIG. 1d illustrates an embodiment of a channel guide 160. Channel guide160 comprises a channel 161, a retention element 163, and an aperture165. Other embodiments may lack one or more of these features and/or mayinclude additional features. While not shown, channel guide 160 may beconfigured to couple to a channel guide cover and at least partiallyenclose channel 161, or such a cover may be an integrated component ofchannel guide 160.

A channel guide may provide a channel, groove, aperture, and/or othersuch feature to accommodate a sensor and/or a sensor subassembly. Achannel guide cover may be coupled to a channel guide to create a pathfor a sensor and/or sensor subassembly. A channel guide may have anysuitable shape and thickness, and may be either disposable or reusable.In embodiments, a channel guide may be configured with one or moreretention elements for mechanically coupling the channel guide to asensor assembly, a sensor assembly component, a SIT, a channel guidecover, and/or any combination thereof. Such retention elements mayinclude slots, protrusions, fasteners, adhesives, etc. Retentionelements may be configured to reversibly mechanically couple the channelguide and another component of a sensor insertion system.

A channel guide may include one or more apertures, depressions, raisedfeatures, etc. to accommodate one or more components such as a sensorassembly and/or its component(s), a SIT, and/or a sensor subassembly. Achannel guide may include a raised surface protrusion that defines apath for a sensor and/or sensor subassembly.

FIG. 1e illustrates a sensor subassembly 170 in accordance withembodiments. A sensor subassembly 170 includes a housing 171, a sensorcontact 173, a sensor contact 174, and a sensor 175. One, two, three,four or more sensor contacts may be coupled to a sensor. A housing maypartially enclose some or all of these components. A housing may beprovided with one or more surface protrusions or other featuresconfigured to mate with one or more features of a channel guide and/oranother component of a sensor insertion system.

Details regarding embodiments of sensor subassemblies may be founddescribed in the figures and text of U.S. Patent Application No.61/037,246, filed Mar. 17, 2008, entitled “Analyte Sensor Subassemblyand Methods and Apparatuses for Inserting an Analyte Sensor Associatedwith Same,” the entire disclosure of which is incorporated by referencein its entirety.

In an embodiment, a sensor insertion system may lack a channel guide. Iflacking a channel guide, a sensor may be held in position by a componentof a SIT and/or by another component.

A sensor insertion system may lack an adhesive member, and thus a sensorassembly may be held to the skin with a separate element such as a band,a belt, a separately applied adhesive such as a dissolvable tissueadhesive, a bandage, a garment, or other means. An adhesive member maybe adapted for placement over the top surface of a sensor assembly.

A sensor insertion system may be provided with features to assist endusers with physical impairments in the use of such systems. Inembodiments, a SIT, a channel guide, a housing, and/or othercomponent(s) may be configured with raised surface details to aid avisually impaired end user in the assembly and/or use of sensorinsertion systems. A housing at least partially enclosing one or morecomponents may be ergonomically designed to be held and/or used forsensor insertion with one hand, and/or the surface of the housing maycomprise surface detail and/or a material to improve the user's abilityto grip the housing (e.g. rubber, plastic, an elastomer, etc.).

In an embodiment, a SIT or other component of a sensor insertion systemmay further comprise a visual, tactile and/or auditory signal conveyingthat a sensor has been inserted, that a sensor has not been inserted,that a malfunction has occurred, and/or that a period of time has passed(e.g. due for insertion of new sensor, shelf life of component hasexpired, etc.). Actuation of one or more components may trigger anauditory signal to convey that actuation was or was not completed. Someembodiments may further include a light source to illuminate skin and/ora component of the sensor insertion system.

A sensor insertion system may be provided with a feature that preventsactuation of the SIT if two components are misaligned or notmechanically locked into position.

Various components of a sensor insertion system may be configured forassembly by an end user prior to sensor insertion. A SIT may be packagedand/or supplied to an end user separately from other components of asensor insertion system, while in other embodiments a SIT may beprovided in combination with a channel guide assembly, one or morecomponents of a sensor assembly, an adhesive member, and/or a sensorsubassembly. Some or all of the components of a sensor insertion systemmay be configured to be mechanically coupled such that they are lockedinto an optimal position for sensor insertion. In embodiments, thelocking of one or more components may be reversed by actuating a releasemechanism.

A channel guide assembly may be provided coupled to a DSA and containinga sensor subassembly. Such a channel guide assembly may then be coupledto a SIT for sensor insertion. A RSA may be coupled to the DSA eitherbefore or after coupling the channel guide assembly and the SIT. A RSAmay be coupled to the DSA either before or after sensor insertion.

A SIT and a channel guide assembly may be provided as a single unit,with one or more components of a sensor assembly being coupled to theunit by insertion of the component(s) into the unit through an openingin the single unit, such as a slot and/or pocket in the top, bottom orside of the single unit. A SIT and a channel guide assembly may beprovided as a single unit with a sensor assembly and/or a sensorsubassembly pre-positioned within or coupled thereto. A SIT and channelguide assembly may be provided as a single unit with a sensorpre-positioned within, requiring only the placement of a sensor assemblyby the user or by another into the single unit.

In an embodiment, a SIT and channel guide assembly may be provided as asingle unit which includes a disposable portion of a sensor assembly,requiring only the placement of a reusable portion of the sensorassembly into the single unit by the user or by another. A SIT andchannel guide may be provided as a hinged unit configured to be openedfor placement of one or more components (such as a sensor assembly or asensor subassembly).

A SIT and/or a channel guide assembly may be provided as one, two,three, four, five or more components to be assembled by the end user.Some embodiments of a sensor insertion system may include a detachablehousing to enclose part or all of one or more components.

FIGS. 2a and 2b show flow charts for methods of using a sensor insertionsystem. FIG. 2a shows a flow chart for a method of using a sensorinsertion system comprising a motive force component (e.g. a SIT) thatis coupled to other components prior to sensor insertion. First, at step201, the motive force component is mechanically coupled to anothercomponent of a sensor insertion system, such as a channel guideassembly, a sensor assembly, or other component, releasably lockingtogether the motive force component and other component(s). Next, atstep 202, the motive force component is cocked and the sensor insertionsystem is placed against skin. A motive force component may beconfigured for cocking before and/or after placement of a sensorinsertion device against skin. At step 203, the motive force isactuated, causing the sensor to be driven into the skin. Actuation ofthe motive force may occur through physical manipulation of a trigger oractuator coupled to the motive force component. Actuation of the motiveforce may occur in response to manipulation of a user interface elementof a sensor insertion tool, such as a button, a key, a touchpad, a dialor wheel, etc. At step 204, actuation of a release element causes themotive force component to become mechanically uncoupled from othersensor insertion system components such as a sensor assembly. Actuationof a release element may release both a motive force component and achannel guide assembly or other component from a sensor assembly. In anembodiment, a release button is not provided and unlocking/dissociationof the motive force component occurs as a result of sensor insertion.For example, a portion of the motive force for sensor insertion may beused after insertion to release/unlock the motive force component fromanother component.

FIG. 2b shows a flow chart for a method of sensor insertion using asensor insertion system that provides sensor assembly components asseparate components to be assembled by an end user, a physician, acaretaker, etc. In step 206, one or more sensor assembly components aremechanically coupled to a channel guide component of a sensor insertionsystem. In step 207, the channel guide/sensor assembly is mechanicallycoupled to a SIT and the coupling causes the SIT and channel guidecomponent to become locked together in position for sensor insertion. Instep 208, the sensor is inserted with motive force provided by the SIT.Last, in step 209, actuation of a release member causes the SIT andchannel guide to uncouple/unlock from the sensor assembly. In someembodiments, the SIT and channel guide may also dissociate from oneanother, while in other embodiments they remain mechanically coupledafter actuation of the release member. In some embodiments, the SIT andchannel guide may be re-used, while in other embodiments one or both aredisposable and/or configured for a single use.

FIG. 3 shows a partially exploded perspective view of a sensor insertionsystem 300. Sensor insertion system 300 may include SIT top housingelement 312, SIT bottom housing element 314, SIT mechanics 320, channelguide 360, channel guide cover 362, sensor assembly 350 and/or sensorsubassembly 370. Housing element 312 may be coupled to mechanics 320 andto housing element 314. Channel guide 360 may be coupled to sensorassembly 350 and to channel guide cover 362. One or more components ofsensor subassembly 370 may be configured to be retained within anopening defined by channel guide cover 362 and channel guide 360 priorto sensor insertion.

A top housing element may have one or more apertures to accommodatecertain features of the SIT (e.g. a release member, a trigger button, acocking handle), allowing the features to be accessible to a user. Ahousing element may also include one or more apertures for indicatingthe status of the SIT (e.g. cocked or uncocked, positioned or notpositioned for sensor insertion, etc.) and/or for accommodating a light,a speaker, or other feature. A top housing element may be reversibly orpermanently coupled to a bottom and/or other housing element with one ormore screw members or pins, an adhesive, a hinge, a snap, a rivet, aclip, or other fastener(s). Alternatively, a housing element maycomprise one or more integrated protrusions, slots, and/or otherfeatures configured to allow mechanical coupling of the housing elementand another component without additional fasteners.

A bottom housing element and/or a top housing element may have surfacefeatures configured to accommodate one or more parts of a sensorassembly or channel guide assembly and/or one or more members formechanical coupling of components. A bottom housing element may includean aperture configured to accommodate the coupling of a channel guideassembly to the bottom housing element, and/or an aperture toaccommodate one or more other components of a sensor assembly.

While FIG. 3 shows two housing elements, embodiments may have one, two,three, or more housing elements. A housing element may be constructedfrom plastic, resin, a polymer, or any other suitable material. Ahousing element may be constructed of a lightweight, inexpensive,durable, and rigid/semi-rigid material. The color/opacity/translucenceof a housing element may vary as desired, and may vary even amongdifferent parts of a single housing element—for example, someembodiments may include a housing element that is clear in one area forimproved viewing of the SIT mechanics and opaque or semi-opaque inanother area.

FIG. 4 shows a perspective view of a sensor insertion system 400. System400 includes a top housing 412, a bottom housing 414, a cockingindicator window 416, a trigger button 424, a cocking handle 432, and achannel guide 460, Top and bottom housing may be mechanically coupledand may enclose at least some portion of the SIT components. Channelguide 460 may be mechanically coupled to housing 414 and/or to the SITcomponents. Top housing 412 may have one or more apertures and/orsurface features to accommodate cocking indicator window 416, triggerbutton 424, and cocking handle 432. A cocking indicator, such as acocking indicator window, is configured to convey to a user that themotive force component is or is not cocked. Alternatively, cocking maybe indicated by an auditory, vibratory/tactile, or other visual signal(e.g. a light, a color change, protrusion of a feature, etc.).Alignment, or lack thereof, of one or more components may be signaled byany of these means alone or in combination.

FIG. 5a illustrates a perspective view of the interior mechanics of asensor insertion tool (SIT) 500 (with the housing removed) configured toprovide a motive force for sensor insertion, In FIG. 5b , SIT 500 isshown mechanically coupled to a channel guide assembly 560. FIG. 5cillustrates a cutaway view of SIT 500 mechanically coupled to a channelguide assembly 560. FIG. 5d illustrates a partially exploded perspectiveview of SIT 500.

The embodiment illustrated in FIGS. 5a-5d comprises a left frame 521 anda right frame 522, a cocking handle 532, a cocking handle screw 533, acocking arm 534, a double torsion spring 540, a double torsion springpin 542, a release member 544, a release member compression spring 546,a trigger button 524, a trigger pivot 525, a trigger arm 526, a fronttrigger compression spring 536, a rear trigger compression spring 538, aleft extension spring 548, a right extension spring (not shown), anextension spring pin 547, a hammer pin 529, and a hammer 528. FIGS. 5band 5c also include a channel guide assembly 560 with retention element563 and retention slot 564. Additionally, left frame 521 and right frame522 include a hammer channel 523.

Left frame 521 and right frame 522 are mechanically coupled such thathammer channel 523 accommodates hammer pin 529, which is positionedhorizontally through hammer channel 523 such that one end of hammer pin529 protrudes through each frame 521, 522. Trigger pivot 525, extensionspring pin 547, and double torsion spring pin 542 are likewisehorizontally positioned to protrude through both frame members. Doubletorsion spring 540 is mechanically coupled to a cocking mechanismcomprising cocking arm 534, cocking handle 532, and cocking handle screwmember 533. Double torsion spring 540 also encircles double torsionspring pin 542 and passes through a notch/channel of the coupled frames521, 522.

Trigger button 524 is mechanically coupled to left frame 521 and rightframe 522 by a surface feature and/or fastener. Trigger button 524 ismechanically coupled to front trigger compression spring 536, whichpasses through a vertical aperture in trigger arm 526 and isaccommodated by a surface of left frame 521 and right frame 522. Fronttrigger compression spring 536 applies upward pressure on trigger button524, increasing the amount of force that the user must apply to triggerbutton 524 to release the hammer, and improving the ergonomic feel oftrigger button 524. Rear trigger compression spring 538 is in mechanicalcontact at one end to an interior surface of a top housing (not shown)and in mechanical contact to an indented surface of trigger arm 526 atthe other end, applying a downward force to the rear of trigger arm 526.Trigger arm 526 pivots a limited distance around trigger pivot 525.

Release button 544 is positioned below trigger arm 526 and is coupled toleft frame 521 and right frame 522 by extension spring pin 547, whichpasses horizontally through an aperture in release button 544 and alsothrough left frame 521 and right frame 522. Extension spring pin 547 iscoupled at its right end to the right extension spring (not shown, butsymmetrical to spring 548) and at its left end to left extension spring548. Hammer pin 529 is coupled in the same manner to the other ends ofthe right extension spring and left extension spring 548.

In operation, the SIT may be coupled to a channel guide assembly.Pressure is applied to cocking handle 532 in an upward direction by auser to cock the SIT for sensor insertion. Pulling upward on cockinghandle 532 forces hammer pin 529 and hammer 528 upward along hammerchannel 523, and pulls left extension spring 548 and the right extensionspring backward and upward, loading energy in the extension springs.With cocking handle 532 in an upright position, trigger arm 526 tiltsaround trigger pivot 525 due to downward force applied to the rear oftrigger arm 526 by rear trigger compression spring 538 (which pushes therear of trigger arm 526 downward). As cocking handle 532 is released,the newly positioned trigger arm 526 stops the hammer 528 from returningto its initial position at the bottom of hammer channel 523, cradlingthe bottom of hammer 528 within a surface feature configured to matewith hammer 528.

Hammer 528 may then be released by pressing trigger button 524, whichforces the trigger arm 526 to pivot such that the rear of trigger armmoves upward until it no longer accommodates hammer 528 within hammerchannel 523, releasing hammer 528 to be forced rapidly along hammerchannel 523 by the energy loaded in the extension springs.

After sensor insertion, the SIT and the channel guide 560 may beuncoupled/unlocked from the sensor assembly by applying pressure torelease member 544. Release member 544 is pushed toward the back of theSIT, pushing retention member 566 outward such that vertical retentionmembers adapted to retain a sensor assembly are pushed away from thesensor assembly. This causes the SIT and the channel guide to beunlocked and/or disengaged as a unit from the sensor assembly, whichremains on the skin. The SIT may then be disengaged from the channelguide 560 by manually pushing retention element 563 with one or morefingers. In the illustrated embodiment, retention element 563 may bepushed to the left (as represented in the figure) in order to disengagethe SIT from the channel guide 560, but in other embodiments a retentionelement may be pushed in one or more other directions, such as forward,backward, up, or down in order to disengage the SIT from the channelguide 560.

A SIT may be securely coupled and/or reversibly locked to a channelguide through one or more retention elements/features, such as retentionelement 563, retention member 566, and/or retention slot 564. In someembodiments a SIT may be securely coupled and/or locked (eitherreversibly or irreversibly) to a channel guide through one or moresnaps, screws, pins, or other mechanical fasteners. A SIT may be pressedagainst a channel guide such that a retention feature of the SIT and/orchannel guide locks the SIT and channel guide into position for sensorinsertion. A channel guide may be pressed against a sensor assembly forlocking in the same or similar manner. A retention element may be usedfor locking components together, for separating components after sensorinsertion, or both. For example, a retention element may be configuredto be mechanically coupled to a component of a SIT (e.g. the frame, arelease button, a pivot, a trigger arm, etc.) and may be uncoupled fromthe SIT by actuation of a release button and/or by manipulation of theretention element itself. In an embodiment, a retention member (e.g.retention member 566 shown in FIG. 5b ) may operate to securely couple asensor assembly to a channel guide, and actuation and/or force appliedto a release member (e.g. release button 544 shown in FIG. 5b ) mayforce the release member against the retention member, pushing theretention member away from the sensor assembly and uncoupling the sensorassembly from the channel guide. In some embodiments a release mechanismmay comprise two or more retention members and/or release elements thatinteract to release a sensor assembly from a channel guide. Inembodiments, pressing a release button may push a firstrelease/retention element backward to contact a second release/retentionelement, and the second release/retention element may then push againsta sensor assembly, separating the sensor assembly from the channel guide(see e.g. FIG. 9f , described below).

The number and configuration of SIT components may vary amongembodiments. For example, a SIT may comprise a single frame member,while other embodiments may include electronic circuitry and/oradditional features. One or more spring members may be replaced withanother source of motive force such as a carbon dioxide cartridge.

A SIT may be individually packaged/provided. In other embodiments, a SITmay be packaged/provided with additional components of a sensorinsertion system.

FIGS. 6a-6d illustrate a channel guide assembly 600 comprising a channelguide 660 and a channel guide cover 662 in accordance with variousembodiments. FIG. 6a is a partially exploded view of a channel guideassembly 600. FIG. 6b shows the channel guide 660 and channel guidecover 662 in position for sensor insertion. FIG. 6c shows surfacefeatures of a channel guide assembly 600. FIG. 6d shows surface detailsof a channel guide cover 662.

A channel guide assembly 600 may have an aperture 665, a retentionelement 663, retention members 666, a channel 661, a retention slot 664,and/or a channel guide cover 662. Channel guide cover 662 may compriseprotrusions 667 on one or more surfaces to assist in retention andalignment of an associated sensor subassembly (not shown). Channel guide660 may be configured for integration with a SIT, a sensor assembly, asensor subassembly, or with any combination of these. In an embodiment,a channel guide assembly 600 may be disposable and may be discardedafter a single use.

A channel guide and channel guide cover may be provided separately,together, or as a single unit in which the channel guide cover is notremovable from the channel guide. A channel guide and channel guidecover may be provided with a sensor subassembly pre-positioned withinfor insertion. A channel guide may be provided with a sensor assemblyand/or a SIT, either separately/uncoupled or as a coupled unit.

A channel guide cover may include one or more protrusions or pairs ofprotrusions configured to retain a sensor subassembly in a position forinsertion until a motive force is applied to the sensor subassembly.Protrusions may also or alternatively improve or maintain properalignment of a sensor subassembly along the channel of the channel guideafter motive force has been applied to the sensor subassembly.

FIGS. 7a-7d illustrate embodiments of a sensor subassembly. FIG. 7billustrates a partially exploded view of a sensor subassembly. FIG. 7dillustrates a sensor subassembly housing in position for sensorinsertion within a channel guide assembly.

Embodiments of a sensor assembly such as those shown in FIGS. 7a-7d mayinclude a housing 771, encapsulant 772, sensor contacts 773, and/or asensor 775. A sensor 775 may be retained within a housing 771 withencapsulant 772. Housing 771 may be shaped, or may include one or moreprotrusions and/or surface features, to allow one or more surfaces ofhousing 771 to mate with a channel guide 760 and/or channel guide cover762. For example, a housing may include a feature such as keel 776 toretain/accommodate a sensor and/or to be retained within a groove orchannel of a channel guide.

A sensor subassembly may include one or more sensor contacts configuredto make electrical contact with a sensor assembly upon insertion of thesensor through/into skin.

In an embodiment, a sensor subassembly may be retained within a channelguide assembly until a motive force is applied, moving the sensorsubassembly downward and causing both sensor insertion and electricalcontact between the sensor subassembly and a sensor assemblymechanically coupled to and/or retained within an aperture of a channelguide.

FIGS. 8a-8b illustrate a reusable sensor assembly (RSA) that may bemated to a disposable sensor assembly (DSA) in accordance with variousembodiments. A RSA may comprise a housing 881 with one or more surfacefeatures configured to allow reversible coupling and/or locking of theRSA to a DSA or other component, such as latch receptacle 897. A RSA mayfurther comprise electronic circuitry and/or a power source such as abattery. In the illustrated embodiment, a RSA includes a printed circuitboard top layer 882, a printed circuit board layout 883, a printedcircuit board bottom layer 884, a battery 885, four RSA sensor contacts886, and a RSA cover 887. RSA sensor contacts may be coupled to RSAcircuitry and may be configured for electrical communication with one ormore sensor contacts of a sensor subassembly. A RSA housing may includeone or more apertures through which the RSA sensor contacts are exposed.In some embodiments, a RSA may receive, store, and/or transmit signalsrepresenting analyte measurements from an individual.

FIGS. 9a-9c illustrate a DSA which may be mated to a channel guideassembly and/or a RSA in accordance with various embodiments. FIGS.9d-9f illustrate a DSA coupled to a channel guide assembly and/or a RSA.A DSA may comprise an adhesive patch 995, a housing 991, one or moregaskets 994, sensor subassembly retainer clips 996, a sensor channel999, a latch member 992, and/or a skin contact member 998. As shown inFIG. 9a , a DSA/housing may include raised surface features 990, a skincontact element 998 and the terminal portion of channel 999. Latchmember 992 may cause retention and/or locking of a RSA to a DSA untilengaged directly or indirectly by a release mechanism and/or a user. Askin contact element 998 and/or other bottom surface features of a DSAmay operate to stretch and/or pull skin taut in preparation for sensorinsertion. In an embodiment, skin contact element 998 may comprise oneor more sections joined to the bottom surface of a DSA, and the one ormore sections may be configured to splay outward in response to pressure(e.g. pressing skin contact element against skin causes skin contactelement to splay outward, stretching skin).

An adhesive patch may be made of any suitable material such as plastic,natural fibers, an elastomer, a polymer, silicone, etc. An adhesivepatch may have one or more antimicrobial characteristics and/or includean antimicrobial substance. In some embodiments, an adhesive patch maybe at least somewhat gas/liquid permeable.

One or more surface features 990 may be included to facilitatemanufacturing and may be absent in a DSA provided to an end user. Forexample, in some embodiments one or more surface features 990 mayfunction as energy directors for ultrasonic welding of an adhesive patchto the bottom of the DSA, and may be at least partially flattenedduring/after welding. Surface features 990 may also operate to couple toan adhesive patch 995, to allow airflow and/or moisture evaporationaround skin under the DSA while the DSA is retained on the skin, and/orto accommodate surface features of other components of a sensorinsertion system. While surface features 990 are shown in FIG. 9a asbeing positioned around the edges of the bottom surface of a DSA,embodiments vary as to the number and positions of bottom surfacefeatures. In embodiments, bottom surface features may be arranged inrows, circles, grids, or other suitable patterns. Some embodiments maylack bottom surface features and/or a skin contact element.

A DSA may be provided to secure a RSA as part of a sensor assemblyand/or to facilitate electrical communication between a RSA and asensor/sensor subassembly. A DSA may be adapted to remain on the skin ofa user after sensor insertion. Adhesive patch 995 may secure the DSA tothe skin of a user. While adhesive patch 995 is shown positioned on abottom surface of a DSA in FIGS. 9b and 9c , in other embodiments anadhesive patch may be supplied separately for placement over the topsurface of a DSA and RSA after sensor insertion. Channel 999 may beprovided within a DSA at various angles to the skin, and may beconfigured to accommodate a portion of a sensor before/after sensorinsertion.

A DSA may be provided with one or more gaskets 994 to provide a sealbetween a RSA and the DSA housing, as shown in FIG. 9b . A DSA may beconfigured to mate to a channel guide assembly for sensor insertion.Sensor retainer clips 996 may be provided to retain a sensor subassemblyhousing or other component of a sensor subassembly. Retention elementssuch as sensor retainer clips may be retained within a recess configuredto accommodate the shape of a sensor subassembly such that motive forceapplied to the sensor subassembly drives the sensor subassembly down asurface of a channel guide and into the recess to engage the retentionelements/retainer clips. The retention elements/retainer clips may holdthe sensor subassembly to the sensor assembly after insertion of asensor, maintaining the sensor and sensor subassembly in electricalcontact with a RSA while coupled to the DSA.

To accommodate a sensor subassembly and/or sensor, a DSA may beconfigured with a groove or other feature within a recess, with thegroove/feature corresponding to a protrusion or other surface element ofthe sensor subassembly. In the illustrated embodiment, a DSA is shownwith a recess comprising a groove/channel to accommodate asensor/subassembly.

FIGS. 9d-9f show a DSA mechanically coupled to a channel guide assembly.A DSA may be configured to snap into place within an aperture or otherfeature of a channel guide 960. Retention members 966 may, when pushedby a release member/mechanism, uncouple the sensor assembly (including aDSA and a RSA) from channel guide 960. A channel guide groove 961 may bematched to a sensor channel 999 such that the components form acontinuous channel when mechanically coupled and/or releasably locked incontact.

In operation, a DSA may be mechanically coupled first to RSA 981 beforecoupling to channel guide 960. In some embodiments, a DSA may bemechanically coupled to channel guide 960 and may then be coupled to RSA981. A motive force may be applied by a SIT mechanically coupled to thechannel guide assembly, striking/propelling a sensor subassembly withsufficient force to drive the sensor subassembly housing into a recessor other surface feature of the DSA, where retention clips may securelycouple the sensor subassembly housing to the DSA. Apertures in the DSAmay be configured to accommodate sensor contacts of the sensorsubassembly, which may pass through the apertures to contact RSA contactelements. The DSA and RSA may be retained on the skin until the usefullife of the inserted sensor has passed, at which time the DSA may bediscarded and the RSA re-used with a new DSA and other components of asensor insertion device.

In some embodiments, as shown in FIG. 9f , a channel guide may includeone or more features configured to interact with a release element torelease the channel guide from a sensor assembly or a SIT. In anembodiment, a feature of a channel guide may be configured to retain asensor assembly/SIT prior to sensor insertion and also to release asensor assembly/SIT after sensor insertion. In FIG. 9f , a releaseelement 967 of a sensor assembly is configured to engage a component ofa SIT (e.g. a surface of a release element/button) prior to sensorinsertion, and a release element 968 is configured to engage a sensorassembly prior to sensor insertion. In the illustrated embodiment,release element 967 is configured to allow mechanical coupling ofrelease element 967 to a release member such as a release button (seeFIG. 5c , showing a cutaway side view of a SIT with release button 544).Release element 967 may be flexible or semi-flexible and may beconstructed of any suitable material, such as plastic and/or anelastomer. Pressing the release button may push the release element 967backward, causing the release element 967 to disengage from the releasebutton. Alternatively, pressing the release button may force the releaseelement 967 backward and downward to press against the release element968, causing release element 968 to press downward against the sensorassembly with sufficient force to disengage the sensor assembly from thechannel guide. In an embodiment, release element 967 may disengage fromthe release button after the sensor assembly has been disengaged fromthe channel guide. In another embodiment, release element 967 may firstdisengage from the release button, uncoupling the SIT from the remainingcomponents, and release element 968 may then be manually pressed todisengage the channel guide from the sensor assembly.

In embodiments, a release element and/or retention element may bespring-loaded, elastomeric, flexible, and/or configured to apply tensionto one or more other components/features, A release/retention elementmay be formed as an integral feature of a component (e.g. a channelguide, DSA, RSA, sensor assembly component or SIT component) or may beadded to a component. In some embodiments, a release/retention elementmay be configured to be used for only one release, while in otherembodiments a release/retention element may be configured for multiplereleases.

Although certain embodiments have been illustrated and described herein,it will be appreciated by those of ordinary skill in the art that a widevariety of alternate and/or equivalent embodiments or implementationscalculated to achieve the same purposes may be substituted for theembodiments shown and described without departing from the scope. Thosewith skill in the art will readily appreciate that embodiments may beimplemented in a very wide variety of ways. This application is intendedto cover any adaptations or variations of the embodiments discussedherein. Therefore, it is manifestly intended that embodiments be limitedonly by the claims and the equivalents thereof.

What is claimed is:
 1. A method of inserting an analyte sensor throughskin, comprising: providing a channel guide at least partiallycontaining an analyte sensor subassembly, the analyte sensor subassemblyhaving an analyte sensor and electrical contact members corresponding toelectrical contacts of a sensor assembly, the channel guide configuredto be mechanically coupled to the sensor assembly prior o insertion ofthe analyte sensor; and providing a motive force to the analyte sensorsubassembly such that the analyte sensor at least partially exits thechannel guide and at least partially enters the skin, wherein the motiveforce is provided by a sensor insertion tool configured to bemechanically coupled to the channel guide prior to insertion of theanalyte sensor, wherein the channel guide and the sensor insertion toolare further configured to be mechanically locked together prior toanalyte sensor insertion and configured to be releasable from the sensorassembly after sensor insertion.
 2. The method of claim 1, furthercomprising providing a sensor insertion tool configured to provide saidmotive force, the sensor insertion tool being configured to bereversibly mechanically locked to said channel guide prior to analytesensor insertion.
 3. An analyte sensor assembly comprising: a firstcomponent, the first component having electrical contacts and circuitry;a second component, the second component configured to be mechanicallycoupled to the first component, the second component further configuredto mechanically retain a third component coupled to an analyte sensorsuch that the analyte sensor is electrically coupled to the firstcomponent after insertion of the analyte sensor through skin, whereinthe first and the second components are configured to be mechanicallycoupled before insertion of the analyte sensor and wherein the first andsecond components are further configured to be retained on the surfaceof the skin after insertion of the analyte sensor.
 4. The analyte sensorassembly of claim 3, further comprising an adhesive member disposed onan outer surface of the first or the second component, the adhesivemember configured to retain the first and second components on thesurface of the skin.
 5. A channel guide, comprising: an elongatedhousing configured to be reversibly mechanically locked in contact withan analyte sensor assembly and having a vertically protruding interiorregion and an aperture; and a channel defined by the verticallyprotruding interior region of the housing, the channel providing apassage through the channel guide, said channel being configured toaccommodate an analyte sensor subassembly.
 6. The channel guide of claim5, further comprising a channel guide cover configured to be releasablycoupled to an outer surface of said vertically protruding interiorregion, wherein a portion of the analyte sensor subassembly is retainedbetween a surface of the channel guide cover and said upper surface ofsaid vertically protruding interior region.
 7. The channel guide ofclaim 5, wherein the channel guide is further configured to bereversibly mechanically locked to a sensor insertion tool prior tosensor insertion.
 8. The channel guide of claim 7, wherein the channelguide is further configured to be releasable from the sensor insertiontool by actuation of a release member of the channel guide.
 9. Thechannel guide of claim 5, wherein the elongated housing comprises arelease element configured to unlock the analyte sensor assembly fromthe channel guide.
 10. The channel guide of claim 5, further comprisinga further protrusion on the vertically protruding interior regionconfigured to align the analyte sensor subassembly for insertion of asensor associated with the analyte sensor subassembly into skin.
 11. Thechannel guide of claim 5, further comprising a skin contact memberdisposed on an outer surface of the channel guide, the skin contactmember adapted to tauten skin prior to analyte sensor insertion.
 12. Asystem for inserting a sensor through intact skin, comprising: a sensorsubassembly comprising a sensor; a sensor insertion tool configured toapply motive force to the sensor subassembly; a channel guide configuredto retain the sensor subassembly prior to sensor insertion and furtherconfigured to be mechanically coupled to a sensor insertion tool; and asensor assembly comprising a first component and a second component, thefirst component comprising electronic circuitry and electrical contacts,the second component configured to be mechanically coupled to the firstcomponent and to be releasably locked to the channel guide, wherein thesensor assembly is further configured to be retained on the surface ofthe skin after insertion of the analyte sensor and wherein the secondcomponent is further configured to mechanically retain the sensorsubassembly after motive force is applied to the sensor subassembly. 13.The system of claim 12, wherein one or more of the sensor subassembly,the channel guide, the sensor insertion tool, and the second componentis disposable.
 14. The system of claim 13, wherein the system isconfigured for first coupling the first component to the secondcomponent, second coupling the sensor assembly to the channel guide, andthird coupling the sensor insertion tool to the channel guide.
 15. Thesystem of claim 13, wherein at least one of the sensor insertion tooland the channel guide includes a release member for releasing thechannel guide and sensor insertion tool from the sensor assembly aftersensor insertion.
 16. A method of inserting a flexible sensor directlythrough intact skin, comprising: providing a sensor insertion systemcomprising a sensor insertion tool, a guide channel, a sensor assemblyand a flexible sensor, the channel guide configured to be releasablylocked in mechanical contact with the sensor insertion tool andincluding a channel within which the flexible sensor is retained, thesensor insertion tool providing motive force for driving the flexiblesensor through the channel and into intact skin, and the sensor assemblycomprising electronic circuitry; wherein the sensor insertion toolcomprises a hammer for driving the sensor toward the skin, a cockingmember for pulling the hammer away from the skin under tension, atrigger member for releasing the hammer, and a release member forreleasing the sensor insertion tool and the channel guide from thesensor assembly.
 17. The sensor insertion method of claim 16, wherein atleast part of the sensor assembly is reusable.